The term “port light” is used throughout this document to mean a port window for a marine vessel. While the subject of this disclosure and the prior art are described using the term “port light”, the terms “port window” and “window” could be used to describe port light disclosed herein.
A variety of types of port lights, both openable and non-openable, have been available for installation on cabin and hull walls of boats for many years to provide natural light and, in the case of openable port lights, ventilation.
Traditionally, such port lights were fabricated of glass mounted in metal frames. These frames were generally constructed from brass, stainless steel, or other corrosion resistant metal. While the metal frames are extremely durable, the frame materials are quite expensive and frames constructed entirely of these metals can be quite heavy, thereby adding significant weight to the watercraft.
In an effort to combat the expense and additional weight, frames constructed from aluminum have been used. Aluminum, however, is susceptible to corrosion; especially in salt atmospheres such as are encountered in marine applications. Corrosion of aluminum frames may be prevented by painting the frames, but this maintenance effort is not always pursued; also, paint does not adhere readily to aluminum. Therefore, where a diligent painting program is pursued the port light frames must be repainted frequently.
In an effort to overcome the disadvantages associated with aluminum frames, a frame is fabricated from plastic and resins were introduced. The lenses used in these frames are generally a transparent pane of plastic or resin material. An example of a port light material used for marine applications would be a pane of Plexiglas™ having a shape that corresponds with the frame. These frames have the advantage that they are made entirely of synthetic materials which are resistant to corrosion and which can be colored to harmonize with the remaining structure in which they are installed. The frames are either bonded or screwed to the basic boat structure peripherally of the opening. Where provided, an interior trim frame is bonded or screwed to the interior of the boat structure for the purpose of ornamentation.
These frames are generally secured to a boat placing them through a hole in the hull and using some type of adhesive to bond the frame to the hull. Generally, the thickness of the frame material is relatively thin. Accordingly, the frames flex readily and the adhesive bond between the pane and the frame may break in response to such flexing. Where screws are used, the area of the frame around the screw hole is subject to additional stress when the frame and hull are flexing. This stress can cause the frames to crack around the screw locations. Additionally, the perimeter of the frame and the areas around screws are susceptible to leaking, especially when the adhesive fails or the frame cracks.
When port lights made from either plastic or aluminum are constructed so that the port could be opened for ventilation and then latched closed to secure the port in rough water, another major problem can occur. If the hinges and the mechanisms for securing the port in a closed position are made from plastic, they can become worn over time and fail. Plastic hinges and latching mechanisms also tend to crack due to stress on the port light that is caused by twisting in the hull. This is especially likely to happen right at the point where the hinge is attached to a frame containing a lens or pane of glass. When the plastic is cracked it is subject to catastrophic failure, which can cause a serious emergency when a vessel is out on a large body of rough water.
Cast aluminum hinges are subject to cracking in the same locations as plastic. Where steel pins are used in aluminum hinges, the hinges are more likely to corrode. If the corrosion is left unchecked, the hinge could fail when the boat is twisting due to rough water.
Other methods of installing port lights have also been tried with varying degrees of success. One method is to directly bolt plastic sheets to the side of a cabin to form a port light. Direct bolting has disadvantages, in that the manual labor required for bolting is costly, and the rough edge of the hole in the side of the cabin is unsightly. Another method is to cement plastic panes to the outside of the hull, thereby reducing the installation costs. However, there still remains the problem of the unsightly edge of the port hole in the side of the cabin and the problem associated with the adhesive bond failing due to the boat flexing. Additionally neither of these methods addresses the leaking problems discussed above.
Some companies have molded frames directly into the cabin side and have cemented the plastic panes into these frames. However, this involves complex molds and the difficult operation of removing the cabin sides from the molds. Also the edges of the panes have to be beveled, thereby increasing the expense of the port light.
In addition to the problems discussed above, there is a potential for water to leak into the interior of a boat cabin, in the area of the frame, around the periphery of the port light. This is especially the case near the bottom of the frame where water has a tendency to collect when a boat is rocking from side to side. To combat this potential for leaking, various drain configurations are used. Most of these drain configurations involve some type of grooves or channels running at a right angle to the face of the port light on the frame.
Most commercially available port lights are constructed so that the main portion of the fame is installed from the inside of the hull. Some of these frames include an outside finish ring but it is not uncommon that such a finish ring is not included. Because these frames are installed from the inside, the water that runs out of the drains can still leak into the hull around the perimeter of the fame. Additionally, the drains on most frames do not run all the way to the face of the port light and thereby leave an area where water can still collect when the boat is rocking.